Protocol for a randomized controlled trial with a stepped care approach, utilizing PrEP navigation with and without contingency management, for transgender women and sexual minority men with a substance use disorder: Assistance Services Knowledge-PrEP (A.S.K.-PrEP).

Background: In the United States, most (~ 70%) annual newly diagnosed HIV infections are among substance-using sexual minority men (SMM) and gender minority transgender women (trans women). Trans women and SMM are more likely to report or be diagnosed with a substance use disorder (SUD) than their cisgender or heterosexual counterparts and the presence of an SUD substantially increases the risk of HIV infection in both groups. Although Pre-Exposure Prophylaxis (PrEP) is highly effective, initiation, adherence, and persistence are exclusively behavioral outcomes; thus, the biomedical benefits of PrEP are abrogated by substance use. SUD is also associated with reduced quality-of-life, and increased overdose deaths, utilization of high-cost healthcare services, engagement in a street economy, and cycles of incarceration.

Objective: To determine the optimal (considering efficacy and cost-effectiveness) strategy for advancement along the PrEP Care Continuum among trans women and SMM with an SUD.

Methods: This study will implement a randomized controlled trial, evaluating two Stepped Care approaches involving A.S.K.-PrEP vs. standard of care (SOC) to determine optimal intervention strategies for trans women and SMM with an SUD (N = 250; n = 83 trans women; n = 167 SMM) for advancement along the PrEP Care Continuum. Participants will be randomized (3:1) to Stepped Care (n = 187) or SOC (n = 63). Participants in the Stepped Care arm will be assessed at 3-months for intervention response; responders will be maintained in A.S.K.-PrEP, while non-responders will receive added attention to their SUD via Contingency Management (CM). Non-responders will be re-randomized (1:1) to either (a) receive A.S.K.-PrEP + CM, or (b) shift the primary focus to their SUD (CM alone).

Results: Recruitment and enrollment began in May 2023. Recruitment will span approximately 36 months. Data collection, including all follow-up assessments, is expected to be completed in April 2027.

Discussion: Trans women and SMM with an SUD have the two highest HIV prevalence rates in the United States, which underscores the urgent need for effective measures to develop scalable behavioral interventions that can encourage advancement along the PrEP Care Continuum. To improve public health, researchers must identify scalable and cost-effective behavioral interventions to promote PrEP initiation, adherence, and persistence among trans women and SMM who use substances.

Trial Registration: This trial has been registered at ClinicalTrials.gov under the number NCT05934877.